First author: Jonathan Petersson
Shell galaxies make a class of tidally distorted galaxies, characterised by wide concentric arc(s), extending out to large galactocentric distances with sharp outer edges. Recent observations of young massive star clusters in the prominent outer shell of NGC 474 suggest that such systems host extreme conditions of star formation. In this paper, we present a hydrodynamic simulation of a galaxy merger and its transformation into a shell galaxy.
First author: Mike Y. M. Lau
Transit and radial-velocity surveys over the past two decades have uncovered a significant population of short-period exoplanets. Among them are hot Jupiters, which are gas giant planets with orbital periods of a few days and found in 0.1-1% of Sun-like stars. Hot Jupiters are expected to be engulfed during their host star’s radial expansion on the red giant branch. Planetary engulfment has been studied extensively as it may account for observed rapidly rotating and chemically enriched giant stars.
First author: Ian D. Roberts
With MaNGA integral field spectroscopy, we present a resolved analysis of star formation for 29 jellyfish galaxies in nearby clusters, identified from radio continuum imaging taken by the Low Frequency Array. Simulations predict enhanced star formation on the “leading half” of galaxies undergoing ram pressure stripping, and in this work we report observational evidence for this elevated star formation. The dividing line (through the galaxy center) that maximizes this star formation enhancement is systematically tied to the observed direction of the ram pressure stripped tail, suggesting a physical connection between ram pressure and this star formation enhancement.
First author: Wasundara R. Athukoralalage
NGC 4472 is home to five ultraluminous X-ray sources hosted by globular clusters. These sources have been suggested as good black hole candidates in extragalactic globular clusters$-$ a highly sought after population that may provide observational information regarding the progenitors of merging black hole binaries. In this body of work, we present X-ray and optical follow up to one of these sources, CXOUJ1229410+075744 (GCU1). We find no evidence of [OIII] optical emission in GCU1 which indicates a lack of significant evidence for super-Eddington outflows, unlike what is seen in a handful of ULXs in extragalactic GCs.
First author: Fabrizio Tamburini
In our previous work [Tamburini and Licata (2017)] we discussed the hypothesis that the ultrafast periodic spectral modulations with frequency $f_S \simeq 0.61$ THz found by Borra and Trottier (2016) in $236$ main sequence stars from a sample of $2.5$ million spectra of galactic halo stars of the Sloan Digital Sky Survey were due to axion-like dark matter piled up in the center of these stars.
First author: Pankaj C. Bhambhani
Galaxy populations are known to exhibit a strong colour bimodality, corresponding to blue star-forming and red quiescent subpopulations. The relative abundance of the two populations has been found to vary with stellar mass and environment. In this paper, we explore the effect of environment considering different types of measurements. We choose a sample of 49, 911 galaxie with $0.05 < z < 0.18$ from the Galaxy And Mass Assembly survey.
First author: Chenxiao Zeng
The clustering signals of galaxy clusters are known to be powerful tools for self-calibrating the mass-observable relation and are complementary to cluster abundance and lensing. In this work, we explore the possibility of combining three correlation functions – cluster lensing, the cluster-galaxy cross-correlation function, and the galaxy auto-correlation function – to self-calibrate optical cluster selection bias, the boosted clustering and lensing signals in a richness-selected sample mainly caused by projection effects.
First author: Honggeun Kim
Detecting cosmological signals from the Epoch of Reionization (EoR) requires high-precision calibration to isolate the cosmological signals from foreground emission. In radio interferometery, perturbed primary beams of antenna elements can disrupt the precise calibration, which results in contaminating the foreground-free region, or the EoR window, in the cylindrically averaged power spectrum. For Hydrogen Epoch of Reionization Array (HERA), we simulate and characterize the perturbed primary beams induced by feed motions such as axial, lateral, and tilting motions, above the 14-meter dish.
First author: Clara Xu
The observability of Lyman-alpha emitting galaxies (LAEs) during the Epoch of Reionization can provide a sensitive probe of the evolving neutral hydrogen gas distribution, thus setting valuable constraints to distinguish different reionization models. In this study, we utilize the new THESAN suite of large-volume (95.5 cMpc) cosmological radiation-hydrodynamic simulations to directly model the Ly$\alpha$ emission from individual galaxies and the subsequent transmission through the intergalactic medium.
First author: A. Bensberg
Aims. We present an implementation of an algorithm for 3D time-dependent Monte Carlo radiative transfer. It allows one to simulate temperature distributions as well as images and spectral energy distributions of the scattered light and thermal reemission radiation for variable illuminating and heating sources embedded in dust distributions, such as circumstellar disks and dust shells on time scales up to weeks. Methods. We extended the publicly available 3D Monte Carlo radiative transfer code POLARIS with efficient methods for the simulation of temperature distributions, scattering, and thermal reemission of dust distributions illuminated by temporally variable radiation sources.
